Apr 25
Why iray?
I’ve been getting peppered with emails, PM’s, facebook messages, smoke signals, you name it about why I’d use iray and/or why anyone else should. Well, it’s just another digital tool in our ever growing software toolbox. While I was eating supper tonight I prepared a few examples showing what I feel are benefits to iray. Read on for more…
Why have I started using iray so much lately? Well, for me and the projects that I’ve been working on lately it’s been pretty useful and can provide some great results. Yes, there are some restrictions/limitations to deal with but IMHO it’s quite useable for the product-vis and to some degree the architectural-vis communities. I hesitate on the architectural-vis side of things because typically architectural interiors can be quite time consuming to render with path-tracer type applications.
This holds especially true on interiors illuminated by a few small light sources or small windows. You’d have to give iray a lot of fast hardware at a scenario like that in order to achieve decent render times. Architectural exteriors are usually pretty good with path-tracer type applications. You get more light/bounced light in areas in a more efficient/faster manner than on an interior.
Character renders will be difficult with iray since currently there isn’t support for a Sub-Surface-Scattering material. So if you’re a character person, you will not be as pleased with iray. Likewise VFX artists will not find it very helpful as it lacks volumetric support at least at this time as well as the general inability to “cheat” things as you can with other rendering applications.
Then there’s the ever popular topic of hardware. OMG, what a whirlwind of opinions that topic opens up these days. It’s almost as though the rendering application wars have moved over to hardware wars. Simply put, right now to efficiently use iray you need a GPU that supports CUDA. From what I’ve read Nvidia cards are the only cards that support CUDA…so you’ll need to use an Nvidia GPU. Which GPU should you use with iray? The one with the highest number of fast CUDA cores available AND has an amount of on-board memory to hold your scenes, texture maps, and render output size AND comes in at a pricetag you can live with.
FWIW I also have an existing thread on the topic of GPU’s with iray HERE. If you haven’t already read it, be sure to check it out for more info on GPU’s, scene size, etc..
Before I dive into the meat & potatoes of this post let me first say that this IS NOT a mental ray vs. iray post. I do compare things here but it’s not meant to bash one or the other, I’m merely explaining a point. Both mental ray and iray are great rendering solutions when used on the right scenes.
I thought it might be useful to not only discuss some of the upsides to iray, but show them. First up let me provide some hardware details and such. Hardware used is a whitebox (home built workstation) with (1) Quadro 6000 as the primary GPU, (1) Tesla c2070 as the secondary GPU, and finally (1) Tesla c2050 as the third GPU…and a small nuclear power plant powering it all. Yes, I know such a configuration is extreme overkill for the following renders…but I usually can’t render my actual work scenes on anything less than 4GB. Sometimes I get lucky and a work scene will weigh in around 3GB hence the Tesla c2050.
Anyway, all the images below were rendered at 1200 x 1200 pixels using only the GPUs (no CPU) via the iray manger script. I’ve reduced all but one to 800 x 800 pixels for faster loading times. I’ll explain why I didn’t downsize one image later. I’ll share the render times but if you’re using a newer GTX type card keep in mind that you may actually find your render times to be faster than mine since those are typically clocked faster than the Quadro/Tesla cards. Yes, that stinks for me but IMHO if I can’t render my work scenes on a GPU (like those fast GTX cards) then it’s of no use to me (other than some sweet, sweet gaming).
Finally, here we go. Up first is glossy reflections & refractions (12 minute render time):
Glossy reflections, refractions, and dof..oh my
They look great with iray and render pretty quickly with the right setup. Sure, there are ways to speed up glossy reflections/refractions in mental ray (env.blur shader), but there are limitations to those options and you may lose time in configuration. With iray you just dial down the glossy values and hit the render button. Also of note is the DOF. That’s basically free with iray meaning there’s no render time hit for using it like you would see in mental ray. Of course there are drawbacks to rendering DOF vs. adding it in post but that’s not the point here.
Here’s another glossy example, this time with metal (3 minute render time):
glossy metal reflections look great as well
Next I threw in a cutout map with some metal material to see how the cutout function works with iray (3 minute render time):
A&D cutout maps work well
Self-illuminated materials are WONDERFUL in iray (6 minute render):
Dude, I wouldn't touch that thing.
HDR Illumination with iray produces nice illumination and shadows that are difficult to achieve with mental ray (2 minute render time).
good area shadows from HDR illumination
Just to help show the HDR illumination & shadows a bit better I switched to another HDR (3 minute render time):
Another HDR illuminated example
Up next is the image that I didn’t scale down. I thought the details would be better viewed at full-res. This is a HDR illuminated scene with a material that has a bump map applied. As you probably know it’s difficult to get a nicely detailed bump effect out of mental ray when using indirect illumination. Indirect illumination and bump map detail isn’t an issue with iray (3 minute render time):
Very detailed bump mapping with iray even with HDR illumination
And the last image I have for this particular post is displacement. Yes, it works with iray as well (4 minute render time):
Good displacement with iray as well
99 comments
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Some great examples Jeff! I still haven’t gotten to use iray in production much as my gpu just doesn’t pack in enough ram to handle most of my work. Thanks for wading in ahead of the rest of us! It’s very helpful to see what your experiences have been thus far.
Thanks for this great demo.
I’m been looking around for a while now, I posted on chaos group forum, MR forum… but I can’t get any answer, so you may be able to answer as you seems to be using gpu render intensivly even on interior scene.
- How can we find out the amount of ram the scene will request from the GPU?
Is the info of ram display in the render dialog during a cpu render the same than the one requested during GPU render?
thanks for your feedaback.
“How can we find out the amount of ram the scene will request from the GPU?”
The exact size should be provided via the render message window during a GPU render (not CPU render). If you need to know the amount prior to a test render then You could guesstimate that based on the info I’ve provided in my iray FAQ (item #14).
Hi Jeff
Thanks a lot for this comprehensive article, it seems that iray is a great solution with promising results.
About CUDA and the hardware thing,I’ve found out that ATI has it’s alternative technology formerly called ATI Stream and now called AMD APP which uses the GPU for other applications processing.
I believe it’s not only a hardware war but also it has a software side. iray supports CUDA but doesn’t support AMD’s APP unlike programs like Cyberlink which supports both technologies.
I like NVidia for their innovations but ATI proved that they can make the cut with smart prices at no hardware quality loss.
“I believe it’s not only a hardware war but also it has a software side. iray supports CUDA but doesn’t support AMD’s APP unlike programs like Cyberlink which supports both technologies.” – Good point. I too would like to see more choices in hardware and software compatibility with the various hardware. More choices = WIN for the customer.
Hi Jeff, in witch hardware config you rendered those images??
I need this info to compare to my system.
thanks
The GPU’s I used are mentioned in the article itself & the power supply is a 1200 watt modular unit.
It might be a win for the consumer, but it would be bad for Nvidia. They make the cards, and they make iray. Their incentive for developing iray is to push more of their cards.
It all looks great, But does iRay work with Mr Sun? From what I read it suppose to, but No matter how I try I can’t get it to work. Render remains absolutely black. Unless I add Mr Physical Sky map as an environment. only then I get ANY illumination in the scene.
Is is a bug or am I doing something wrong?
“But does iRay work with Mr Sun? From what I read it suppose to, but No matter how I try I can’t get it to work.” – It doesn’t really use the mrSun for direct illumination. It uses the physical sky instead. But you’ll still need to use the mrSun to specify sun placement in the sky/scene.
Take a look at the daylight system scene/info I posted here (scene02): http://jeffpatton.net/2010/10/iray-sample-scenes/
Nice looking renders but your throwing ~$10,000 worth of GPU at it…
I’d like to compare this to say Vray or Modo with a workstation with $10k of CPU’s in it..
I agree. I too would be interested in seeing how $10k in CPU power would compare in various rendering applications.
I guess there could never be a direct comparison between a biased CPU rendering and an unbiased GPU rendering since you should consider all the time spent tweaking the biased rendering.
That’s a great point though. It would certainly be useful to include those type of stats in a benchmark scene (one must create/apply specific types of material THEN render). However, I think that may be too subjective because everyone works at different paces Lot’s of aspects to consider in such a benchmark.
Really good article Jeff, thank you. I have seen a lot of the visualization people pick up iRay, and I have seen a lot of discussion come from this side of things, but I don’t think even Mental Images knows the full extent of what they could have here. While your right it does have some current disadvantages in character animation, for those who work in the video post side of things, it can be something special. In a world of render passes having the GPU tackle some passes as threads and the CPU tackle others could save deadlines. I’d like to see it possible to set up a render pass render in Max that you could specify the renderer for each pass to harness the best out of all of them. Imagine your shadow pass, alpha, lighting, z depth and id passes (the billion calculations but lighter math tasks) all being done done while your having the CPU do the 500 really difficult math passes. Or, am I crazy here? With Crazy high color depth EXR and Red footage these days having passes saves…well you know where I am going for matching in.
Hi Jeff,
I have been using iray since it was first released and I really love it. I use it with a single Geforce 580 GTX which has plenty of ram for me, at 1.5GB.
I have two major wishes for the next version of it. 1) Interactive, iterative rendering, so it can compete with vray RT 2) Region focus rendering, so you can focus all of your gpu power on a certain area of the render frame for testing. Vray RT also does that.
Also, I have heard that 3dsmax 2012 is supposed to be faster rendering of some materials with iray, but I have not seen any difference. Have you?
Richard Yarlett
http://www.iray3d.com
Great post Jeff!
Thanks for sharing your findings.
Hi Jeff,
Really great site and post – even though I am a Maya user I am still very curious about iRay.
I know that you have shared your material render test scene in the past and I was hoping that maybe you could also share this current version used to make these iRay samples? I have looked around but cant seem to find a current version in OBJ or Maya format. I wanted to make some materials for the vRay FBI Shader library and share them via the Chaos Group site and your scene is the best test setup I have seen. Thanks in advance!
-Nick
Go to mrmaterials.com for the Maya version, XSI version as well as the 3ds Max version.
Just registered and downloaded them. Thanks so much for the heads up.
-Nick
Tnks Jeff, when will u make a new dvd?
I dont use 3ds max a lot, but I apply the same in Maya with mray.
Iray is working only via string options in Maya, but works very well in this 2012 version. So far, only using it for “pre-viz” but didnt used it a lot yet.
I don’t have any plans at the moment to make any DVD’s/training material. Glad to hear iray is running smoothly in Maya, albeit by string options.
amazing results with HDR! as u said it was kinda hard to achieve this illumination realism with MR…
1 – Was the technique the same as in MR? Just throw the hdr into the skylight?
2 – What about that white point configurations? Have u played with it?
I also loved the displacment results, and its also great to see a bump working so well with just an indirect light!!!
Do u have any idea about how the “gamer” cards would handle these same scenes?
Thanks Jeff!!!
1 – HDR is used in the environment. Skylights aren’t needed with iray…but you can use one to disable the default lighting.
2- I don’t ever tinker with the white point configs, etc with HDRs, even with mental ray. 32-bit/Def. exposure works best for me without any adjusting.
A new/fast gaming card should render such a simple scene a bit faster than my config.
That was a faith comparing, but I think I should wait a bit more (maybe 3Ds Max 2013). as you said this war is going somewhere that we will benefit.
Thanks again
How about some complex scene? The memeory limit of the gpu pretty soon cuts in isnt it? Foliage rendering? IMO Gfx Cards needs to have at least 4-6GB memory in order to be useful for all tyes of rendering.
Hey Jeff,
Great materials. Love the lightning.
Not so much related to this blog post, but I’ve been looking everywhere and can’t find anything on this topic:
I’ve heard many times, even from Kaplan himself, that there is a ray focus brush in iRay to focus the whole GPU on a certain area. I cannot actually find anything in the 3ds Max documentation on this, or find it in the interface. Have you come across this? It would be great for headlights and things, rather than stopping the render when most is clear and doing a region render on parts I want to clear up further.
Thanks,
Andrew
Yes, unfortunately we can’t access that iray brush feature from within 3ds Max. Probably has something to do with the 3ds Max frame buffer…hopefully they (Autodesk/mi) will find a way to make that work inside 3ds Max.
Jeff, you say:
“Anyway, all the images below were rendered at 1200 x 1200 pixels using only the GPUs (no CPU).”
In Max, how do you control what is used for rendering? How do you tell Max to render using only the GPU?
You can do so by entering the string commands directly or IMO the easiest way is to just use the iray manager script.
Why, thank you!
I like your work, It’s beautiful~
Lovely renders you have Jeff. Ive tried to use iRay combined with a self illuminating material to light a certain area. Ive rendered up to 15 minutes and have a noise problem. It seems like iRay would have to render at least 30 minutes for my Quadcore with 4 Gigs of RAM to reduce this noise. Any ideas?
Link to my render: http:www.drmoore3d.com/iray.jpg
“iRay would have to render at least 30 minutes for my Quadcore with 4 Gigs of RAM to reduce this noise.” – rendering with iray using the CPU will be much slower than with some FERMI based GPU’s.
hi jeff
can i ask for displacement map of roofing ? its so great !!!
You can download it HERE.
Note: Yes, it’s a very small map at 94×97 pixels.
Excellent article!
Great post with very nice examples. I thought iray wasn’t mature enough to use in production but you proved me wrong.
Thanks a lot for your inspiration!
Hi Jeff!
Greetings and much thx for tidious works that help us. Am wondering, when you do your renders with multiple cards, are they on sli mode or how do u use all the cards on the same render. Perharps i can also ask, the GTX 590 with 3GB, can it create animations on high quality renders using iray. thanks again
1. SLI isn’t needed in order to render with iray. It just uses whatever compatible GPU’s are installed and/or you can specify which to use via script commands or the iray manager script.
2. There’s some existing discussion on the GTX 590 a few posts above yours so be sure to check those posts out for the memory concerns associated with those particular cards.
Great article Jeff and superb sample images, i know that iray requires a minimum gpu ram of 1gb, i happen to have 2 nvidia 8600 gts 512mb each in sli, will i be able to use it with iray? will iray recognize it as a single 1gb card?
No, currently iray will not combine memory from multiple GPU’s whether they are SLI’d or not. You may want to check this entry as well as it houses a fair amount of GPU information: http://jeffpatton.net/2010/11/gtxquadrotesla-my-opinion-on-todays-gpu-selections-for-rendering/
Thank you so much for the info, i think its about time to invest in some fermi based gtx cards, cpu rendering really sucks in iray, i cant seem to get the results that i want. thanks again Jeff.
Hi Jeff,
I need you expert advice on a pc build, what processor can you recommend? im choosing between the Intel core i7-2600k sandy bridge 3.4 ghz and the intel core i7-960 bloomfield 3.2 ghz, i know that sandy bridge is the newer one of the two, but im interested in the triple channel memory of the bloomfield, would it matter much if i go with triple channel ram rather than dual channel? im going to be using the pc mainly for 3ds max and mental ray rendering, and hopefully start with iray as well. i hope you can help me out, thank you.
I would check over at the Hardware and Technical discussions forum at CGArchitect.com. I say that because I’m not 100% up to speed on the best CPU’s for rendering at the moment. I do more GPU rendering these days so my CPU is a basic single quad-core model. The people in that forum are more likely to be up to date with CPU based specs than me at this point.
Thanks for the link Jeff, i found some really good answers in that forum, im still in need of a good processor for now since im still doing most of my work in MR, i will be looking into iray soon too so its probably good to invest in a decent GPU as well. thanks again for this thread.
Jeff,
What HDRi did you use for the marble / corian material test – 6th image down (http://jeffpatton.net/Tests/HDRI_illumination02_3m.jpg)
Ta,
Matt
I’m fairly certain it was DH214 from THIS collection.
Hi Jeff,
great interior shots on flickr.
AYou say that most of the lighting is from the HDRI. Are you using the new IBL mode with importance sampling? (new in maya but I guess it’s the same in max) and are you using the brdf shaders or the arch and design shaders?
Cheers,
Steve
Hey Steve,
Thank you. The latest interior renders were made with iray, so no mental ray w/IBL node and/or importance sampling.
I believe most of the materials were arch and design material with maybe a couple of Autodesk materials thrown in there.
Hi Jeff,
thanks for the info.
Where in max are you plugging in the hdri?
Cheers
The HDR is assigned to the scene environment.
Hi Jeff, very nice examples. I have technical question you wrote that you have 3 graphic cards in your computer that rendered this examples. I would like to know how did you set up a system like this with three different graphic cards, so all of them work together without problems.
Could you post the specs of the rest of the parts from your computer please?
Also maybe you would happen to know if I could mix ATI and NVIDIA. I have ATI in my computer at the moment but my mobo has two slots so I was thinking if it would be possible to mix it with NVIDIA. ATI could stay for games and I would like to buy some not so expensive NVIDIA for the CUDA only. Do you think this is possible?
“how did you set up a system like this with three different graphic cards, so all of them work together without problems.” – Basically I installed the cards, booted the machine, let it download/install the drivers, and started rendering.
More complex was going through some hardware conflicts that I had to track-down to my motherboard. I ended up replacing it and the power supply. My current configuration is this:
ASUS P6T7 – Intel i7 960 3.2GHz – 12gb RAM – nVidia Quadro 6000 – nVidia Tesla 2070 – nVidia Tesla 2050 (only used on some scenes) – 1200 watt modular power supply – Windows 7 (64-bit)
Info on the older setup can be found in this other blog post HERE
“Also maybe you would happen to know if I could mix ATI and NVIDIA.” - It might work…I know you can assign whatever GPU you want to use with iray via the iray manager. However, I just don’t know how stable that configuration would be. I personally hesitate on mixing vendors like that because I fear driver conflicts. It may be fine though…I honestly can’t say with any certainty.
If you do try mixing ati & nvidia, please let me know how it goes. I plan on creating an updated iray/hardware post in the near future and I’m sure that kind of info would help others out here.
Sure, I will let you know if it works when I buy it. I am thinking now which one would be good enough. I don’t want anything to expensive. The only thing I care is CUDA other parameters don’t matter to me so much.
Hi jeff.
Just boght a gtx570 thix weekend and its great, but still didnt tested it with iray.
I’m looking foward to buy another vga and “sli” it, but i see that you uses three different models.
Nvidia says that for sli the best is to use the same model, so now i’m confused, since you arebusing differeent models.
This means that if i buy a gtx 590 (great speed and memory, and cheapper than a quaddro here where i live) to sli with my gtx570 it could work?
SLI isn’t used by iray. I also don’t think there’s any 3ds Max 2012 (and older) viewport performance gains to be had by SLI’ing cards. Therefore I don’t believe that SLI really matters to anything other than gaming at this point.
Hey Jeff, nice results as usual!
I’m curious about your setup using iray and vrayRT, have you made some tests?
I did some tests with VRay RT right after upgrading to VRay 2.0 but not enough to make any fair comparisons IMHO. Same holds true for Octane. I have a license of it but I haven’t used it in a while either. At some point I’ll need to try them all again but things are too hectic at the moment.
Thanks for the reply Jeff!
I asked about the vrayRT because you don’t need to export anything and it even support arch & design. And since it works the same way as iray I would expect a very close performance.
Hi Jeff, great work and thanks for taking the time to share your knowledge and experiments.
I don’t think I saw you mention your iray settings (limited as they are), you know, passes, image filtering and others…
Thanks.
can i know why Iray finish render..will appear some noise…?how to clear it?
The longer it renders, the less noise there will be as iray refines (by reducing grain) the image over time. So if your image has noise/grain then it hasn’t rendered long enough. You could also try using some de-noising filters in post applications. Rendering larger than what you need then scaling down can also help reduce noise but larger renders can consume more GPU memory.
Additional GPUs will help it refine the image faster.
Nice tests Jeff, thank you.
Will you be able to do some complex renders? These are good but not showing much production potential of Iray at the moment. Investing that much into hardware and not being able to render complex scenes is not, let’s say, smart move.
Most (90%) of my work asks for more than 6GB of memory, is there card at market today, that offer this?
Because, if I am able to do only product shots and maybe some simple scenes that huge investment can not be justified.
Best,
“Will you be able to do some complex renders?” – I have these two ongoing articles: THIS and THIS
“Most (90%) of my work asks for more than 6GB of memory, is there card at market today, that offer this?” – Not that I know of.
“if I am able to do only product shots and maybe some simple scenes that huge investment can not be justified.” – Indeed, iray is not a “one size fits all type render”. It’s not the best choice for everyone or every scene (no single render engine is IMHO). However, I do believe iray has a place in the market but it’s definitely a limited market at the moment.
Hey Jeff
thanks for the great info, been looking into this for awhile and now with MAX 2012 and iray been integrated so easily I am moving my system up to a GTX 560 card tomorrow, but before I did I did some test of just straight cpu just to test the iray system out.
Post some images on my facebook if anyone is interested and will post iray cuda enabled ones asap.
http://www.facebook.com/daniel.m.najera1
Jeff,
Thanks for posting your work and sharing your findings!
Do you have a link to the scene used in this thread?
thanks!
Great article! So nVidia did a nice job. What i read about iRay was ussualy just about performance using nVidia HW and Tesla technology and the performance boost was impresive
hi jeff been reading a lot of stuff on your website about iray, its prob the most informative out there so thank you for that, now i I know you have prob answered this question a million times before but me and a friend are trying to start up our own animation company and have a scene that’s up to nearly 5gb already and we have characters to do yet so looks like it will exceed the 6th limit on the tesla memory limit, is the only way round this to cheat using smalling textures etc, wait for larger graphics cards to be produced or do you know of any plans to share the gpu memory across multiple gpu’s also one more question, when you use CPU and gpu in iray is the system memory shared across gpu that way? sorry if these questions are stupid but iray is supposed to be this big change in rendering which it has the potential to be if it wasn’t for the memory issue can you advise me
anymore please thanks for your time in reading this
“looks like it will exceed the 6th limit on the tesla memory limit, is the only way round this to cheat using smalling textures etc, wait for larger graphics cards to be produced or do you know of any plans to share the gpu memory across multiple gpu’s” – Correct, for the GPU rendering you’re limited to what’s available on the GPU and scene/texture optimization is critical to that. As of today I don’t know of any plans/options for cumulative sharing of memory between GPUs or plans for GPUs with higher amounts of memory. I certainly hope either or both would be on the near horizon. As an outsider looking in it sure seems like a higher memory GPU would be easier/faster to create for the market than cracking the GPU memory sharing issue. Time will tell I guess.
“when you use CPU and gpu in iray is the system memory shared across gpu that way?” – No, the workstation/system memory isn’t shared with the GPUs when using the CPU with iray. The CPU can use all the memory available to it but the GPU is still limited to it’s on-board memory. When rendering with the GPU’s I find it easier to think of them as mini render nodes that just happen to be located inside my workstation. I can send jobs to them but I can’t exceed their memory footprint.
“sorry if these questions are stupid but iray is supposed to be this big change in rendering which it has the potential to be if it wasn’t for the memory issue” – Don’t worry, they aren’t stupid questions by any means. These memory (and instancing) limitation are currently one of the bigger roadblocks with GPU rendering that’s preventing GPU rendering from being more mainstream (IMHO). GPU rendering can be used in some production scenarios today, but it’s not optimal for all scenarios at this time. :/
hey jeff many thanks for your quick reply and your answers, one more thing if ya don’t mind, the ram Iray uses, is it the exact memory that 3dsmax shows on your task manager usage? or does it only take the memory needed for the scene and the onboard ram takes care of max usage? if so do u know what ram max uses? I hope ya don’t mind me bending your ear about it but it’s a decision on weather we go down the CPU or gpu route or maybe both, many thanks for your time
There’s more to consider than just file size. Things like the frame buffer/image output size also consume memory on the GPU(s). Take a look through my GPU hardware post HERE, specifically the replies. I’ve provided information there that can help with figuring the GPU load. I also provided info on how the output resolution affects memory consumption by rendering a scene at 1080p, 6k, and 10k res, etc. Lot’s of info in that thread, especially in the replies section.
thxs very much jeff I’ll have a read, I’ll leave ya in peace now lol have a good day man thxs again
Hi jeff, i work for a movie production company for my next project i will be expect to deliver vehicle animations at 2k res to be composited over live action. Since my scenes would mostly be made up of cars, i would to know if a workstation configuration like yours would be capable of handling the final images short animations of scenes full cars.
Hard to say off the hip. It would depend on how complex the car meshes are. Instancing with applications like iray don’t work as you’d expect with a CPU rendering application. Also how many texture maps (and their resolution) will be a factor to consider. FWIW I don’t think the 2k frame buffer itself will cause you much of a memory issue. It usually doesn’t start coming into play until 3k res and higher.
Also keep in mind these GPU rendering applications typically can’t do effects like motion blur (at least at this point in time), which I would imagine is pretty important in your line of work. Of course you can switch render engines (iray doesn’t support render elements either) and output a motion vector pass to add motion blur in post. You probably already know these limitations, but I thought I’d play it safe and mention it for others that may drop by and read this later.
Thanks jeff, effects like you said can be done in post so its out of the question for now , the meshes i use for my cars have up to 190000 polygons, so if i can do the more complex calculations(global illumination, raytracing,etc) quicker using hardware rendering, i think its worth giving a shot. Also, i saw some of your vehicle renders, are the vehicle materials from iray?
“i saw some of your vehicle renders, are the vehicle materials from iray?” – Yes, most everything I’ve worked on this year has been with iray. I gotta say the latest Bunkspeed application is looking very attractive for automotive rendering these days though.
Hey man. Great article, but I have a (silly) question. Can the iray renderer work well on a low end PC ? I still use an Nvidia 9500gt 1GB graphics card and my PC has a RAM of 8GB. I intend to use the iray renderer for architecture scenes mostly ( still saving up for a good PC )
I’d really appreciate it if you could help me out. Thanks
Sure, in GPU rendering applications the GPU will be doing most of the work so the CPU doesn’t matter as much as with a non-GPU accelerated rendering application. You may want to upgrade your graphics card first as your current 1gb doesn’t leave a lot of room for the scene, materials/textures, and frame buffer. I’d probably look around for a deal on a 3GB 580 series GPU. At minimum I’d aim for a 2gb card, but 3gb will give you more headroom to do a bit more. Beyond that you’ll also want to make sure your power supply is up to par before upgrading the GPU.
Hi Jeff! you work is great and shearing your knowledge is great too.
I want to ask you if have you tried i-ray with back burner?
I’m rendering a simple scene. while watching the process on render buffer on nodes everything look ok but when image are saved they get darker. i have checked all my nodes to have the same settings related to gamma values but i don’t get correct results.
thanks in advance!
No, I haven’t tried it with Backburner because I only have one workstation configured for GPU rendering. The problem you describe sure sounds like a gamma issue though. Seems like I’ve heard mental ray users mention this too so it may not be related to iray. Have you tried switching the scene over to mental ray to see if it produces the same problem or if it is in fact limited to iray?
Hi, I have been recently starting to work with iray, and I have noticed the follow.
the amount of memory required for the GPU has to be hight, if you want render at big scale with textures
when I put an HDRI map as enviroment, looks like IRAY cancel or turn off the skylight system, and just keep ilumination with the HDRI map, also I have to give it values as 23 times in the output image rollout.
the initial result is a little blurried in comparisson with the mentalray engine.
I would like to know more about these issues
thanks
“the amount of memory required for the GPU has to be hight, if you want render at big scale with textures” – In the newer release of iray a large frame buffer no longer consumes GPU memory as it did in previous versions.
“when I put an HDRI map as enviroment, looks like IRAY cancel or turn off the skylight system, and just keep ilumination with the HDRI map, also I have to give it values as 23 times in the output image rollout.” - Correct. Iray can use the HDR that you apply to the scene environment to illuminate the the scene, no skylight (or any other light source) is needed for HDR illumination. Just be sure to disable the default lights. As for cranking up the output value, that’s because of your exposure control, not iray.
“the initial result is a little blurried in comparisson with the mentalray engine.” – iray applies a blur to the environment (for smoother lighting). You can control that via the iray manager or manually entering string options.
Thank you for replying Jeff, so I started using iray to render some architectural scenes and I was really impressed even though the final render had alot of noise ( I read your article on how to reduce noise and it helped alot )
Anyway I looked around for a gtx 580 card and they don’t have them here. That means I’ll have to import one. In the mean time could I instead put in another 1GB Nvidia 9500gt card on my CPU ? I already have one installed. And if so, would iray recognize the 2gigs of VRAM ? What about the CUDA cores ? The 9500gt has 32 CUDA cores so would putting another one double both the VRAM and the CUDA cores ?
Thanks in advance
When you add video cards iray, or any other GPU rendering application available at the moment, it will not cumulatively add the GPU memory together. The scene must fit onto EACH gpu separately. It will only use the additional GPUs for rendering provided the scene fits onto their memory footprint.
When working with GPU rendering applications like iray I think it’s helpful to get into the mindset that adding another GPU is like adding a separate render node or additional workstation to a CPU based render farm. Doing so does not add to the RAM in your primary workstation, it just gives you more resources to render with. If you exceed the memory on your extra render nodes or extra workstations those will not be used or it will crash, etc..
Thanks alot for the advice Jeff. I’ll just go for the gtx 580 for now. One more question, lets say I have a scene I am about to render and there are 3 options in the tab, the specified time, number of passes and unlimited time. I noticed that when I specified the time I wanted it to stop rendering I could see the render progress but when I set it to unlimited I couldn’t see the progress, it just stayed at 0.0% rendering, even after 6 hours or more. The final render looked promising though as there was little noise in the scene ( I deleted the windows and put a Mr Portal light instead )
And what if I specified a time of about 3 hours for a scene, will iray finish up the render process perfectly or just hurry up the render to match the time given ?
Sorry for the noob questions.
Thank you !
“when I set it to unlimited I couldn’t see the progress, it just stayed at 0.0% rendering, even after 6 hours or more.” – That’s because unlimited is just that, unlimited. It will render until the power goes out or your machine explodes.
So there’s no end until you cancel/stop the render so it can’t calculate a percentage of completion in that mode.
“what if I specified a time of about 3 hours for a scene, will iray finish up the render process perfectly or just hurry up the render to match the time given ?” – iray renders by refining the grain/noise in the image. It does so at the same speed no matter what duration method you specify (Time/Iterations/Unlimited).
The only difference is when & how it stops refining the image. If you specify 3 hours for a render time there’s no guarantee that 3 hours is enough time to produce a grain free image. FWIW the more you work with it you’ll find that you get a feel for about how long it will take to render a scene with your hardware and you can typically guess at this number. If you configure it for Iterations (number of passes) then you need to roughly know how many iterations are needed to produce a satisfactory result. If you configure it for Unlimited then I suppose it will continue to refine until you stop it or the equipment melts, or the world ends.
Thank you so much Jeff ! I used iray to render and interior scene and I’d like some feedback from you be it negative/positive criticism. Where could I send you the file ? It’s a still image by the way.
hi, how can i obtain that realistic shadows and reflections, is there any tutorial ? I use hdri but I dont obtein that.
There should be lot’s of HDR tutorials around, try site like youtube for video instructions. There should also be a HDR sample scene that ships with 3ds Max (on the sample scenes included in the second DVD). But basically realistic reflections will boil down to realistic material settings. Shadows depend on the light source and which render engine you use. For HDR’s with iray a smaller, brighter light source will produce more pronounced shadows than a broad and/or dull light source. See THIS article for more info on that.
As much as the article is great and inspiring, at the same time it is depressing and it probably took the last drop of hope from me.
Just when I thought that days of Mental Torture ehem! I mean Mental Ray are over and that there is a new Mental Ray based renderer that actually works, and it works simply, intuitively and well…I realize now that I need an insane hardware to use IRay in Archviz and there is no way for me to afford it
I guess this is not my time, I am trying to become an artist and not a programmer…yet the stage that CG is at today doesn’t allow me to be an artist without being a programmer and an expert at problem solving and workarounds.
Hence I am seriously thinking of leaving CG forever.
Its not like its the most appreciated type of job anyway…you have to have no life, sit in front of PC whole day every day, minimal free time per day, be under the constant pressure of finishing the project till the deadline and still get all the bugs errors and stuff…that seems too much for someone as naturally prone to stress as I am.
But still thanks for giving me the last drop of hope Jeff!
Who knows why that is good for! 
-Milos
Hi Milos,
Sorry to hear that you’re considering leaving the CG field. I know how difficult a choice like that can be as I faced it a couple of years ago myself. All of the money we invest into hardware/software is a big aspect to consider in this decision. For me personally, one thing that kept me going was thinking about all the time I had dedicated (and still do) to learning more about CG methods. At that point in my life it felt like if I walked away from CG I would be “throwing away” about 8 years of my life and that was a very hard pill to swallow.
You’re right, one does need to be a bit of a problem solver in this field though. I’ve been fighting between two different render engines for the last few days now trying to get a project out the door. Both rendering applications pose different problems and in the end I had to weigh out which problem was the easiest to fix in post and just go with that one. Sometimes projects go off without a hitch but more often than not something pop’s up out of the blue to throw a monkey wrench into the works and the troubleshooting hat has to go on.
I think I’m drifting off point here.
Bottom line, I know that’s a very tough decision to make. Weigh the pro’s & con’s carefully (and strongly consider your gut feeling about it) and don’t decide in a moment of haste or frustration. As you already know, you don’t need expensive hardware or GPU rendering applications to make great images. Whatever conclusion you make, I sincerely hope it leads to much happiness & success.
Hi Jeff, love your comments and information about Iray!
I’m doing some light rendering with Iray on a i7 2600k with a 560ti 448 cores gaming card and the results are great so far.
With some effort I can get an older gtx 260 for free, do you think adding this would help my rendering times or is the card too slow nowadays to notice the increase?
Great work!
The 260 isn’t bad, should have something near 200 CUDA cores. Not sure what memory configuration that 260 has but as long as your scenes fit onto it, then it shouldn’t hurt to add it…especially if it’s for free.